J.K. Rowling (Joanne "Jo" Rowling) is the writer behind the best selling Harry Potter series. The Potter books have gained worldwide attention, won multiple awards, sold more than 400 million copies and been the basis for a popular series of films.
Aside from writing the Potter novels, Rowling is perhaps equally famous for her "rags to riches" life story, in which she progressed from living on benefits to multi-millionaire status within five years. The 2008 Sunday Times Rich List estimated Rowling's fortune at £560 million ($798 million), ranking her as the twelfth richest woman in Britain. Forbes ranked Rowling as the forty-eighth most powerful celebrity of 2007, and Time magazine named her as a runner-up for its 2007 Person of the Year, noting the social, moral, and political inspiration she has given her fandom. She has become a notable philanthropist, supporting such charities as Comic Relief, One Parent Families, Multiple Sclerosis Society of Great Britain, and the Children's High Level Group. Rowling's mother died of multiple sclerosis, and because of this she became severely depressed for a period of time.
Real people are the basis for her characters, including one of her most famous, Gilderoy Lockhart, though she refuses to say on whom he is based.
Harry Potter is her most famous debut, though she has written other books branching off of Potter, including The Tales of Beedle the Bard, Quidditch through the Ages, and Fantastic Beasts and Where to Find them.
Rowling has millions of fans and is a household name all around the world, so if you write her a letter, don't expect her to answer it. Please note that she doesn't have an email address.